Z9M3 Rear belt Alignment and Tensioner CoreXY

thingiverse

Rear Belt Alignment and Tensioner for CoreXY Z9M3 Zonestar now includes a metal part for belt alignment, which has greatly reduced my belt tension. I have a much smaller belt tension now. This is my second type of rear CoreXY belt tensioner. Each belt has its own "Dial It In" toothed pulleys to loosen or tighten. Along with keeping a single 5m 10mm belt intact to allow for any future end cuts. I must say, my first test print worked better than I had hoped. This is a multipart module for my Zonestar Z9M3 3-in-1 CoreXY large format FDM printer. I have been modifying my unit and still have many future plans once I find the funds to do so. Working with what I had again, I used 2x 60 toothed pulleys. Now that I have a test unit made, I may be able to use smaller pulleys, not a 20 tooth, as I need more contact space with the belt and 3D printed part. Also, this is designed for my units' 3D printed tolerances (ABS filament). I'm not using the factory CoreXY layout or belts; I'm using 10mm (really 9mm) steel core belts from Amazon. So, every brand and type of belt will have different very small changes in thickness. The 3D printed unit must be exact in the space the belt takes up with the pulley. To tight and you will not be able to make changes; any extra may not keep the belt compressed on the pulley. I included the Sketchup source files along with STL for your customization. Ideally, you should be able to make changes, and it will hold its place until secured. Here's how to assemble: 1. Assemble the M4 60mm and nuts. 2. Attach the 60 toothed pulleys to the spacers. 3. Place the M5 bolt through the pulley and attach the washers. 4. Secure the modified 20 tooth pulley to the M5 bolt. Now, let's move on to the verification steps: 1. Move the carriage around and re-measure until square. 2. Once things look square to you and even, start measuring and make changes. 3. Then, secure the modified 20 tooth pulley to the M5 bolt, and the belts will be held in place. Print of a skew test to verify if you want, and then tighten the belts to correct the print. I did a 250mm x 250mm test and was unable to see any difference that would show the unit is out of alignment or askew. The idea is not to modify software or firmware to correct askew alignment. All ya, I'll also be drilling new cable run mount holes for cable management and to raise above the new 10mm belt config (I drilled in the wrong place first time as seen in picture). Working on a smaller version... Will post once designed. Files included: * Z9 rear belt alignment * Z9 rear belt tensioner * Small test for 20 toothed pulley, if your print is tight and does not move then rest of my prints should be good for you, just have to worry about belt thickness. * Sketchup source CAD files for your use Will also need to print or make a higher cable chain support for the rear of the unit. This is the one I made for my 20XX Z9 frame: https://www.thingiverse.com/thing:3052683 Parts List: * 2x M4 60mm and 2x nuts * 2x M4 Spacer 6.33 OD 12.65 L (I have super cheap Caliper, and bought spacer from local hardware store) * 2x 60 toothed 5mm bore pulley * 2x M5 bolt * 2X 20 toothed pulley * Some washers Enjoy! 'mike'